Error Handling#

This page covers error types and handling in bfabricPy.

Consult Exceptions and Errors for a complete API reference for exception types.

ResultContainer Error Handling#

When using client.read(), client.save(), or client.delete(), operations return a ResultContainer.

Note: Empty results are not errors. A query that finds no matching records is valid and returns an empty ResultContainer. Errors only occur for issues like network failures, authentication problems, or server errors.

Automatic Error Checking (Default)#

By default, operations will raise a RuntimeError immediately if they fail:

# This raises RuntimeError if there's a server error
results = client.read(endpoint="sample", obj={"name": "MySample"})

# Access results only if successful
for result in results:
    print(result["name"])

# Empty results are not errors - this is valid and returns an empty list
results = client.read(endpoint="sample", obj={"name": "NonExistentSample"})

Manual Error Checking#

To handle errors without exceptions, use check=False:

# Disable automatic error checking
results = client.read(endpoint="sample", obj={"name": "MySample"}, check=False)

# Check status manually
if results.is_success:
    for result in results:
        print(result["name"])
else:
    print("Query failed:")
    for error in results.errors:
        print(f"  - {error.message}")

Use manual checking when you need to:

Continue processing even if some operations fail
Collect errors from multiple operations
Implement custom error recovery logic

EntityReader Error Handling#

The EntityReader may raise different types of errors:

ValueError#

Raised when:

URI is invalid or from unsupported B-Fabric instance
bfabric_instance parameter doesn’t match client’s configured instance
All URIs in a batch are not from the same instance or entity type

from bfabric import Bfabric
from bfabric.entities.core.uri import EntityUri

client = Bfabric.connect()
reader = client.reader

try:
    # This will raise ValueError if instance doesn't match
    entity = reader.read_uri(
        uri="https://different-instance.com/bfabric/sample/show.html?id=123"
    )
except ValueError as e:
    print(f"Error: {e}")

TypeError#

Raised when:

expected_type parameter is provided but the entity doesn’t match

from bfabric import Bfabric
from bfabric.entities import Sample

client = Bfabric.connect()
reader = client.reader

try:
    # This will raise TypeError if entity is not a Sample
    entity = reader.read_id(
        entity_type="project", entity_id=123, expected_type=Sample  # Wrong type!
    )
except TypeError as e:
    print(f"Type error: {e}")

None Returns#

For read operations, None is returned (not an exception) when:

Entity is not found in B-Fabric

entity = reader.read_id(entity_type="sample", entity_id=999999)
if entity is None:
    print("Sample not found")
else:
    print(f"Found sample: {entity['name']}")

Error Handling

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